Means for setting or testing hydraulic shock absorbers



May 19, 1953 MEANS FOR Filed May 22, 1951 F. A. o. SADLER 2,638,777

SETTING OR TESTING HYDRAULIC saocx ABSORBERS 10 Sheets-Sheet l May19, 1953 I F. A. D. SADL ER I 2,633,777

MEANS FOR SETTING 0R TESTING HYDRAULIC SHOCK ABSORBERS Filed May 22, I951 10 Sheets-Sheet 2 nkkk May 19, 1953 F. A. D. SADLER MEANS FOR SETTING OR TESTING HYDRAULIC SHOCK ABSORBERS Filed May 22. 1951 FIG 3 1O Sheets-Sheet 3 May 19, 1953 F. A; D. SADLER MEANS FOR SETTING 0R TESTING HYDRAULIC snocx ABSORBEIRS Filed May 22.1951

10 Sheets-Sheet 4 uuimsos 5 ms y 9, 1953 F. A. D. SADLER 2,638,777

MEANS FOR SETTING OR TESTING HYDRAULIC SHOCK ABSORBERS Filed May 22, 1951 10 Sheets-Sheet 5 ISO [3! I32 I36 I33 FIG. 5- I34 I00 I08 |Q| 0 a 7 I06 7 I20 ||7 2 C33 IV! us I w an Q a g &

CB |O7 .2 a

May 19, 1953 F. A. D. SADLER 2,638,777

ESTING HYDRAULIC sHocK ABSORBERS MEANS FOR SETTING OR T Filed May 22, 1951 mmT May T9T1953 F. A. D. SADLER 2,633,777

MEANS FOR SETTING OR TESTING HYDRAULIC sHocx ABSORBERS Filed May 22, 1951 10 Sheets-Sheet 7 a g N 8 L M 9 E I h\a Q May 19, 1953 F.,A. D. SADLER MEANS FOR SETTING OR TESTING HYDRAULIC SHOCK ABSORBERS Filed May 22, 1951 l0 Sheets-Sheet 8 o M D W/ W// g fiw m m QWWW W Jim/z May 19, 1953 F. A. D. SADLER 2,533,777

MEANS FOR SETTING OR TESTING HYDRAULIC SHOCK ABSORBERS Filed May 22, 1951 10 Sheets-Sheet 9 FlG.ll.

May 19, 1953 F. A. D. SADLER 2,538,777

MEANS FOR SETTING OR TESTING HYDRAULIC SHOCK ABSORBERS Patented May 19, 1953 MEANS FOR SETTING on TESTING HYDRAULIC SHOCK ABS oamms Francis Antony Dawson Sadler, Birmingham, England, assignor to Girling Limited, Birminge ham, England, a, British company Application May 22, 1951, Serial No. 227,565 r In Great Britain May 23, 1950 --11 Claims. (01. 73-11) This invention relates to new or improved means for setting or testing hydraulic shock absorbers or dampers of the type in which damping of relative movement betweentwo par-ts is effected by the flow of oil or other liquid through one or more valves which are loaded to a predetermined value, f

In the manufacture and assembly of such shock absorbers or dampers it is desirable to employ means whereby the valve or each valve can be rapidly and accurately set or checked for rate of flow and/or opening pressure so that uniformity of operation canfbe ensuredfand the object of my invention is to provide such means.

According to my invention means forsetting or testing hydraulic shock absorbers or dampers. hereinafter called dampers," comprises means for holding a damper and connecting it into a closed circuit for liquid, means for adjustingfavalve in the damper while liquid is passing through it, a power-driven pump or pumps for feeding liquid through the circuit at a rate of flow substantially greater than the maximum flow which can be passed through the damper, valves for controlling the flow of the liquid in the circuit independently of the damper, and means for indieating or measuring the pressure, rate of flow, and temperature of the liquid at one or more points in the circuit. f

The liquid in the circuit, which will usually be oil, should be maintained at a substantially constant temperature so that the viscosity does not vary appreciably, and means for controlling the temperature of the oil and for filtering it are conveniently included in the circuit. F

Preferably the whole of the operations are caused to take place in the proper sequence by Figure 2 is a side elevation of the complete apparatus. I

Preferably, also, means are provided Figure 3 is a diagrammatic view of the layout of one half of the apparatus showing theflow circuits and the inter r'elation of the various parts of the apparatus;

. .2 Figure 4 is a longitudinal section of the fixture in which the shock absorber is mounted while oil is forced through it at a predetermined rate of. flow and a valve controlling the passage of oil from the cylinder is set or adjusted.

Figure 5 is a vertical section on the line 5-5 of Figure 4.

Figure 6 is a vertical section on the line 6-6 F of Figure 4.

Figure '7 is a plan of the fixture.

Figure 8 is a longitudinal sectionof the fixture in which the shock absorber is mounted while a valve in the piston is set or adjusted under flow conditions. F

t Figure 9 is a vertical section on the line 99 of Figure '7.

Figure 10 is a vertical section on the line lO-lflof Figure 8. i

Figure 11 is a planof the fixture shown in Figures 8 to 10. i p I F F 7 Figure 12 is a longitudinal section of. ashock absorber of the type which our improved-apparatus is designed for setting and testing.

The apparatus illustrated is designed for use in afactory or in' a service station or garage for setting or testing hydraulic shock absorbers or dampers of the direct actingte1esc'opic-type in which a piston works in an oil-filled cylinder surrounded by a cylindrical reservoir or recuperation chamber. the piston being carried by a piston-rod working through a gland in a closure which closes one end of the cylinder and of the recuperation chamber. A spring-loaded valve arranged in the piston controls the flow of oil through the piston in one direction and a valve remote fromthe gland controls the flow of oil from the cylinder into the recuperation chamber. his the setting or adjustment of these valves which controls the functioning of the shock absorber'. Further lightly loaded valves in the piston and in the closure forthe cylinder permit the "flow of oil through the piston in the opposite directionand from the recuperation chamher into the cylinder but the loading of these valves does not require adjustment.

The apparatus illustratedlpermits'the setting of the control valves'in the piston and in the closure for the cylinder to be adjusted whileoil is being circulated through the valveat a predetermined rate of fio wandgat a Substantially constant temperature to eliminate errors due to variations in the viscosity of the oil.

oil is supplied through inlet pipes t' by an priming 'pump'drawing oil from a storage tank of substantial capacity and feeding it to the pumps [2, [3 through filters.

rates of flow to separate circuits incwhioh the damper is connected for settingsoilthe valves in the damper piston and in the'ql surefiqr; he

cylinder, but as the two circuits are identical only the second is illustrated in Figure 3'; The

The pumps I2 and I3 respectively supply oil at" predetermined:

fixtures in which the damper is held in the'two circuits differ slightly and these are described in detail hereinafter.

The pump 13 delivers oil under pressure into a pipe 15 leading to an hydraulic rnotor I! which is coupled to and supplies" power to the gearbox l'i andtlre oil from the exhaust side of the' motor is returned to the storage tank by way of awater-cooled-heat exchanger which main,-

tains the temperatureof the'oil in the circuitsubstantially constant; The object of the hydraulic motor I! is to take care of whatever volurneof the'oildelivered-by'the pump His surplus to the volume required in the new circuit and t employ that surplhs useful-ly in providing D we Thedelivery" pipe 16- from the pump is is conneciu'edioy a branch pipef8 to two pistpn-- type selector valves i9 20 operated by a common slidingbar- 21 which is 'actuated by' a control lever 22. When the bar 21 is raised an inclined surface 23 on the bar first opens the; valve ['9 and then after a certain amount oflostmotion a second inclined surface 2%" opens the valve 28.

The rate of movement of the lever ZTiSfQOIltIOHQd by connecting it to'th'e banZ-l through-a damper 25"to -preven t the val-ve 20 from'being openedto rapid-lyafter the valve l9;

When the valve i'9 is opened oilunder pressure isg-supplied througha pipe 2Wtohydrauliccylinder 1', Z8jfiQr" operating'clamps at opposite ell-u sashra -29 m vvhi'chthe damper 30'3is to" a; second selector valve 3| which is operated" y le r. 2" and: s rran d; e ect' e oi irousi 'e therq two cuits; a h, fi'ow fuh t ndar bw'fiow i u t.- a h i c t in= as ofjwhi ch" th -fun tio is; to' limit the inlet pressure on thefiow control valve to a:;maximunr alu er." the outlet pr sur iq i ite te v l e" 3 i iq elr jlinkl 5';v an tput. c trol 363Ifor"th pum t ns iithe'le r s in er ckedi y a c 37 with thecontrol' lever 22 sox that thefe i'22c-an. jb.e Qperated: to op n the valves;

yand'lvun the ey 2 is. in a'pos tiqn corresponding "to t e selection of; the high flow circuit-t Thrqlighi' whivcbever'flowcircuit. s. seleoted the oil is -fed"through, a, ipe. 38; into, the amper b way, qff ne end Qffth ixture.

ande m-r tur v. .ve, 41 t a low-meter. 3 The rate of flow is indibatd by, a rotatin strob e pic. d sc ill minated bx a. neon. lame The lever 32'? also operates The v aft pa sing hrough the. v lve, in, the. damp flowsbr. wax. o i pine, w nc p ratins a visible, flow ndilat and; t r u h. tan emv filters 41 v 4 having two concentric rings of markings 45 cor-- responding to tw predetermined rates of flow. From the flowmeter the oil returns through a pipe d6 to the valve 28 and from there through a pipe 4'! to the storage tank by way of a nonreturn valve andthe oil. coolen, v

The pressure of 'the oil at the inlet of the pump l3'is shown by a pressure gauge 48.

Th pressure of the oil leaving the damper is shown by the gauge 49 which is connected to the outletipipeztll through a trapped line pressure 'l'eSt IiCfiOn' valve 5 0.

The temperature oi -the oil entering the damper islghgwn bjy 'avremote reading thermometer 5|.

gauges-Wand 53 are respectively low and high range gauges showing the pressure of the oilenteringthe'damper, both gauges being connectedtothe pipe 33 by a pipe 54 incorporating a, trappedpressure line restriction valve 55. The low range valve is protected by a safety device 55 incorporating a diaphragm and a valve actuated'b'y the di'aphragmto'preventthe pressure reaching th gauge from exceeding the value permissible on that gauge."

Ail the apparatus illustrated in Figure 3 and described" above and the corresponding apparatus to which oil" is supplied by the pump H arearranged in a casing or cabinet to 'form a compl'ete'un'it which has only'to be connected to a water supply and'an electric current supply and can be 'installied'in'any convenient position.

A practical design of cabinet'is shown in Fig- 11165'1 and 2m which the various parts visible are groupedin'verti-cal panels, 62, W'facingthe operator.

thetop ofthe base in frontof'the panels;

The gauges'fl, ofifbetween'th'e panels show re- I spectively the oil pressurein' the lubrication systenrof the gear-box and the temperature of'the oil leavingthe cooler;

The rate of flow of water through the cooler is controlled by a hand-wheeled on the front of the cabinet.

The startins'and stop'ping'of the motor which drives thepumpsjare'controll'ed by push buttons 6T," 68.'above the hand-Wheel 56'; the main switch andfuse"-box 6S"being mounted on. one side of" the cabinet.

The'level of thejOil in thestorage tank is shown ofth'e cabinet andaccess is obtained to them base, of the cylinder is illustrated, in Figures, 4-,]

Th'e'fi'xture which receivesth'e damper during the setting of the valve in, the closure'for the 5 and 7'.

The fixturecomprisestwo. main parts 8!} and 8|; The part'80is fixed to a'base plate'fll'wh'fle 7% the part 8| is, slidably mountedon two parallel 4:1 in alternating; current cricuit v the. disc,v 7 pends/on the axi ll ne h ofthe damper and'the part is locked in its set position by opposed pegs 87 engaging in aligned holes 88 in the bars. The pegs are carried byopposed pistons 89 working in a transversedouble-ended hydraulic cylinder 90 in the base of the part 8|, and the pistons are urged apart to force the pegs into the holes in the bars when oil under pressure is admitted to a fitting 9| in the centre of the cylinder. This fitting communicates through a passage 92 in the body of the part 8| with a union 93 which is connected to the pipe-line 26 (Figure 3) A shock absorber of the type which the apparatus is designedto set and test is shown in section in Figure 12 of the accompanying drawings. It comprises a cylindrical barrel 94 in which works a piston I95 carried by a piston-rod 95 of which the outer end is fixed in a cap 96 having an eye 91 for the connection of the piston-rod to a part of the vehicle. The piston-rod works through a gland in a head 98 which is adapted to be secured into one end of the barrel and to be screwed into the open end of a cylindrical reservoir or recuperation chamber I96 which normally encloses the cylinder but is not required for the setting operation.

.Passage of liquid through the piston in one direction is controlled by a lightly loaded disc valve I91 of which the setting is not critical. Passage of liquid through the piston in the other direction is controlled by a spring loaded valve I98 engaging a seating in a fitting I99 which is screwed into the piston-rod 95 and secures the piston to the rod. The seating with which the valve I98 engages is at the outer end of an axial bore 200 in the fitting I99 communicating with a transverse bore 20I in the piston-rod. The valve I98 is loaded by a spring 202 arranged between the valve and a ring 203 screwed into the outer end of the fitting I99. There is a hexagonal opening 204 in the ring to receive a key or the like, and the loading of the valve is adjusted by screwing the ring into or out of the fitting. The end of the cylinder remote from .the head 98 is closed by a base fitting 99 containing a spring-loaded valve 205 which controls the passage of oil from this end of the cylinder 1nto the recuperation chamber I96.

The setting of this valve is effected by rotating a hexagonal nut 206 on a stem 20'! of which the inner end has a hexagonal or other head or has a hexagonal nut fixed to it.

The fixture shown in Figure 4 is employed to hold the damper during the setting of the valve 205 in the base fitting 90. The damper is shown in dotted lines in Figure 4.

To fit the damper into the fixture the head 98 is moved axially on the piston-rod away from the end of the cylinder barrel and the base closure 99 is separated from the barrel. The head is received and held in a seating or clamp in the part 80 of the fixture as shown in Figures 4 and 5. The clamp is divided in a horizontal plane containing the axis of the damper, the lower half 1 of the clamp being fixed and the co-operating upper half being in a hinged block I00.

The block is hinged at one side by a pin IOI to the upper end of a vertical spindle I02 slidably mounted in a bore in the fixture. On the other side the block has two parallel lateral projections I03 adapted to be engaged by opposite ends of a locking pin I04 mounted in a lever I05 pivoted to rock about a pivot I06 in the upper end of a second vertical spindle I01 slidably mounted in a bore in the fixture. A handle I08 7 us g: lds up armssure n Phl ft-hand 6 onthe block I00 extends laterally onone side of and beyond the lever I 05. l

The lower .ends ofthe spindles are slotted to receive substantially horizontal levers I09 to which the spindles are pivotally coupled by pins I I0. The levers are fixed at oneend in a transverse shaft III which forms a fulcrum for them and theother ends of the levers ar connected by a transverse. bar II2. AtIthe centre of its length this bar, carries an upstanding rod II3 of which the upper end isengaged by the piston I I4 of an hydraulic cylinder II5 which is connected by a union IIG to the pipe-line 26 (Figure 3). When oil under pressure is supplied to the cylinder II5 by the opening of the valve I9 the levers are moved, downwardly about their fulcrum and draw the spindles I02 and I01 downwardly to urge the block J00 against the fixed lower part of the clamp and so to clamp the head 98 of the damper in position as shown in Figure 5. The lever I05 islocked in the engaged position by a roller I ll against which bears the head of a spring-loaded plunger'IIB mounted in an axial bore in the spindle I01.

When the valve I9 is .closed and the cylinder H5 is de-energised the spindles I02 and I 0'lare free to rise and are raised by a spring II9 con-. nected between a fixed anchorage and an arm projecting downwardly from the fulcrum shaft III. The roller II! can then press the plunger II8 downwardly andthelever I05 can be swung outwardly on its pivot toiree the pin I04 from the projections on the block I00.

The block can then be swung upon its pivot to release the damper, the block being resiliently retained in the raised position by theengagement with acurved edge on the block of a roller on the upper end of a spring-pressed plunger I20 mounted in a bore in the spindle I 02. l

h A seal is made between thetwo parts of the There is thus a sealed space I24 in the clamp around the piston-rod of the damper between the head 98 and the end of thejcylinder barrel and this space is in communication withthe cylinder barrel. 1

A union I26 connected to the pipeline 38 (Figure 3) communicates by way of a passag I21 with an inclined drilling in the head 98 which, when the damper is inuse, conducts any oil which leaks past the piston-rod into the recuperation chamber. Any oil flowing through this drilling during the setting operation is returned into the main flow circuit between the fixture and the flow-meter so that the total flow shown by the meter is the same as under normal working con- 1 ditions.

The space I24 comrnunicates by way of a passage I28 with an air release valve I29 mounted on the top ofthe block I00. Any air present in the oil passes into the closed left-hand end of the valve housing,through a bore I30 in a plunger I3I, past a .ball I32. which is normally spaced from the end of a rod I33 fixed in a closure I34 for the other end of the housing, and out to atmosphere through a groove I 35 in the closure I34.

A; spring I36 normally holds the plunger in such-1a positionfthat the ball I32is clear of a seating at the end of. the bore I30 so that air can pass freely, but if oil passes up into the valve end of the plunger and moves/the phi-ng'erte' the right against the spring Ioa'dingse'that the-here I30 is closed by the hall I32 wh-iehiahuts against the red Wand the: oi-leazinot'eseapet The other end oi-the damper e ylintier hancelis 5 sl idably engagect'in-an annular seal mom a bore afitti'ng ls tl-fcoupl ecttd thepart 8! of the fixtu-re. At an-mtermediate Quintin i;ts1 erig'th the barrel is: pressewdown between two eoxiical rub-- hergripping members I142" which hold it down whi1e-theother eermeetions are bemg made The base closure 99013 the: eyliriderharre]; which: the 'val te to beset IocaSteti is received in an annular seat *3 in anextensieni MA 01 "the part BI and is held in position ageii ns't afi internal shoulder int'he extensi'emby a collar backed phang'ers I itiinthe fitting MI jointflbetweenthe extensiomli tahd i the?" fitting I is made by amamniil'ai" seal M18? The Hexagonal: headon'the-vaivefistemzw'l in th'bIOSfl-L 9}! is reee'ivect in a. complementary" ofiening'fin a plate M7! whiehis'urged against the c su -I' e by a spring M8 The-adjusting imt 2I I i's'erigaged by fingers on the inherent? ofa sIeeVe I N gen pi'ed to: a hollow spindle lfi fi w'h ch extend through a glahdI S I 'ahdWarrfes'a I I rd -W eel I52 on= its olitenend.- Thus-rotatiort of-the hamwheel rotates the 5 adjustingnut be adiih etite' loading 'of the val ve i 11 the'elosur'e 9 After the setti'ngha'sbe'en effeeted' the fitting e moved away from." thpa)'1t 8| ahdffihbf cldsiirQS 1S pushed-out be the extension I bi a m-ng ei" I 53? passing axially threngh the spi-ndle liwarid" hav ing al-khobeh-fit's hi1 1" end I of the*vgal'veioil -is'fed hate I-Efl the fitting." 4-I=between mam-s of the"bai'1 e1-"ant the b cIosu'te Q'IFof'flth' dampem th-is sp'e ca a ime" I56 connected t; ne'pipeqme as. Aftefpassiiig th-r ug h' the valve in the *eldsui the oil-passes oiit thr'oii'gl'a' a passage I 51 we uniiitr l 5 is; connected t6 we pipe 1iiie"-3 The passage vaIve-I' 58 to "-preeene 'oii f mm the res-t of the system draining back when the damper is takeifoiit of thefi'xtfire; I I I Figure 6' shew-s a fiirther asse e I GI ZI "connecting the ontl'efiipaissag' I 51 with-a "liliibnfFBI ft o which: teammatesa piiie leading to 'the gauge 9 which shows the outlet pressure. I

In this" case; however, the main 011 fee'd intEjthe'darnper isin'tcrth slt'iad I14 in" theme-m by;- way of a passage I62 from a union I63 whit: connected tothe"pip 1'ine-" tram the flow cofi valve. Anothefiitiioli"l' fi lifediii L W II to the pre'ssu're'gaiiges whichsho th inietbresaf' sure, aridth bnIbof'a' remote-reading therm om eteris-inse'pt Thhther end' of in a seali-hg ring" ably coupledto a spindle I'IGI The pmngeris urged into eng'agement with the valve by ashrine: I 'II 'mefspmdie I'I'Ii'extehdsjthrough a; gland H2 in the fixture and has ahanc'bwheel I13 on its outer end'fox rotating aw adj-fist theva l-ve.

After theo'fl has passed through the vaive it leaves the fixture through a passage I74" coritairiing a non retur n valve I15 andleading to a u nior'r I15. I I I I When setting the valve in the piston the base closure 99"oi?'the" cylinder is of course 'left off.

sett ng of either valve can he effected very rabidi y and easily. Aftei the damper has been insei-tedinto the appropriate fixture the opera? tei'" si'mp'1 3/' Has'to actuate conti-o'l levers in the 'cbifreet sequence and to watch the flow meter andpiess-ure'gauges while he adjusts thevalve by means'of the liand-wiieelon the fixture untii thepressiire's on the gauges cofi esp'dnd to those giverr preset stationaiw pointers. Uniformity of setting can thus be readily ensured? l'elai-in' f 1 Apparatus for setting mam-uric dampers of the direct-acting type" in which d am-ping" of refs;-

1 tive movement between two parts is'effiected by the flow 0f oil "01' other liquid through-valves loc ated 'in the piston and in the cylindefclosiii'e' oif a' cyii 'der and piston assembly; eohipris 'g"a closed ICiTQu-it for Imam, mea for n01 g 'a' darn e i-arid connectingit in tofsa-id circuit, a powerfdriven pump for f'eedhig iiquiti into} the cii 'cu'it' at a rate of saw substantially r aterthan the' maXiiniim rate which ca-n' be tiassed through the damper, nie'an's'fo'r ad-jhsti ng a valve inf the dampe'i'whi-l'e liqnid 'isjlias ing thr'oiigh it; mans fo co'nt'rolli g' the flowof li'diii'dfiri the circuit independently of the I damper, and e for in'd i'eating the pressure' and 'rateof flow of the'liq iiidf at poin-ts in the eirc uit'} II I I I 2'; A'p ziaratus' for setting" hydiaulic eepest? the 'clii e'et-a c' tirig typgjin which damping of rela ti movement between two pa t s' is efiecteii by ow' of oil oi othei liqiiid through valvsxle sated in" the piston a-iid' in the eylintier' elh sm e' offa cyiiiidei and'pi'st'on assembly; eoflifirisi CICS C d Ci TCIiit fer li'qiiidi hydraiiil ibali yat tedi' clamps for holding a damper ceiirieetirig it iritosaideire 'lit, a power-driven pumpifor f-'ling l iqu id intot e circuit/[at a rat'e'of flow sub'-'= staritiali'y gTeater thaiif the maximum ratewhieh can ,be passed. through the dam-her; means tor adjusting}; vah/e' the dame-er While liqu'i'diis pass ng-through=it meansfofeontrtilling the now damper, a valve for supplying lit fiid from'the circuit 'to'' hydraulically actuated! cramps, means to indicating the? pressure": of the; liquid" ifi the-Iciremt' on each" sideof the damper; and means for indicating them-ateef fiowhfiiiquid:

through the 'damper'. II

3; Appalatusas ih ciaiin "2 whereinsaid meanscircuit comprise a 'main centrol mm, a sele'-toi ,vaitemidtwe censt am flow circuits annange'd 1m parallel between saidseleeter vaiire and theme: ciiitf and" giving difie'rent 'rat'e s' of flow, said condamper are operated successively by a single control member.

5. Apparatus as in claim 2 wherein said means for controlling the rate of flow in the circuit comprise a main control valve, a selector valve, and two constant flow circuits giving different rates of flow arranged in parallel between said selector valve and said circuit, each of said constant flow circuits incorporating a flow control valve and a valve loader.

6. Apparatus as in claim 2 wherein the means for indicating the rate of flow in the circuit comprise a flow-meter indicating two predetermined rates of flow, and the means for controlling the flow of liquid in the circuit independently of the damper incorporate valves providing two different rates of fiow and means for selecting either rate of flow.

7. Apparatus as in claim 2 wherein means are provided for filtering the liquid in the circuit and for maintaining it at a substantially uniform temperature.

8. Apparatus as in claim 2 wherein said circuit comprises a tank for liquid, a pump to which liquid is supplied from said tank, a gear-box, an electric motor driving said pump through said gearbox, an hydraulic motor coupled to said gear-box, and means for supplying to said hydraulic motor liquid delivered by said pump and not required in said circuit.

9. Apparatus for setting hydraulic dampers of the direct-acting type in which damping of relative movement between two parts is eifec-ted by the flow of oil or other liquid through valves located in the piston and in the cylinder closure of a cylinder and piston assembly, comprising a closed circuit for liquid, a power-driven pump for delivering liquid into the circuit at a rate of flow substantially greater than the maximum rate which can be passed through the damper, means for controlling the flow of liquid in the circuit independently of the damper, means for indicating the pressure and rate of flow of the liquid at points in the circuit, and means for holding a damper and connecting it into the circuit, said means comprising a fixture in two parts of which one is fixed and incorporates a clamp for one end of the damper and the second receives the other end of the damper and is adjustable towards and away from the other and incorporates manually operated rotatable means for ecu-operating with and setting a valve in the damper while liquid is flowing through it, and means being incorporated in the fixture for feeding liquid to the damper on one side of said valve and taking it from the other side.

10. Apparatus as in claim 9 incorporating hydraulic cylinders for actuating the clamp in the first part of said fixture and for locking the second part of said fixture relative to the first, and means for supplying liquid from the circuit to said cylinders.

11. Apparatus for setting hydraulic dampers of the direct-acting type in which damping of relative movement between two parts is effected by the flow of oil or other liquid through valves located in the piston and in the cylinder closure of a cylinder and piston assembly comprising two closed circuits for liquid each incorporating a fixture for holding a damper and connecting it into said circuit, a power-driven pump for feeding liquid into the circuit at a rate of flow substantially greater than the maximum rate which can be passed through the damper, means for adjusting a valve in the damper while liquid is passing through it, means for controlling the flow of liquid in the circuit independently of the damper, means for indicating the pressure of the liquid in the circuit on each side of the valve, means for indicating the rate of flow of the liquid through the valve, an electric motor driving the pumps in both circuits, a tank from which liquid is supplied to both pumps and to which liquid returns after passing through both circuits, means for maintaining the liquid at a substantially constant temperature, and a cabinet in which all of said parts are mounted.

FRANCIS ANTONY DAWSON sADLE-R.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 982,773 Wood Jan. 24, 1911 2,101,228 Willard Dec. 7, 1937 2,129,763 Hart Sept. 13, 1938 

